As far as safety is concerned, Martin says it’s definitely the safest jetpack built to this point, but acknowledges that, “Safety is a relative thing.” He is also not sure what the greater purpose of the invention will be.

According to The New York Times, “since the 1960s, several real jetpack designs have been built from metal, plastic and propellant. None has flown more than a minute. Mr. Martin’s machines can run for 30 minutes.”

The machine is technically not a jet, either. MSNBC.com science editor Alan Boyle says that the Federal Aviation Administration would probably consider it to be an “experimental ultralight airplane, equipped with a gas-powered, V-4 piston engine and two ducted fans that provide the lift.”

Jetpacks entered the public imagination in the 1920s, with the story of Buck Rogers and his “jumping belt.” James Bond further popularized the idea when he escaped to his Aston Martin with the assistance of his trusty jetpack in the 1965 movie “Thunderball.” Then in 1991 Disney released “The Rocketeer,” in which the protagonist used a rocket-propelled backpack to combat Nazis.

Inventor Glenn Martin calls his invention “the world’s first practical jetpack.” He revealed his technology at the annual air show EAA AirVenture in Oshkosh, Wis. Martin was not sure what his invention will be used for, but he quoted Benjamin Franklin on seeing a hot-air balloon and answering the question “What good is it?” Franklin said, “What good is a newborn baby?”

The New York Times provides a short history of jetbacks since they appeared in popular culture in the 1920s, starting with the story of Buck Rogers and his ability to “leap over cities with the aid of a ‘jumping belt’”.

MSNBC.com science editor Alan Boyle writes: “Whether the Martin Jetpack technically qualifies as a jetpack is debatable. It's not the type of rocket belt that James Bond wore in ‘Thunderball,’ and it's not anything like the jet-powered, wearable wing that a Swiss daredevil cranked up to 186 mph in May. As far as the Federal Aviation Administration is concerned, what Martin has is an experimental ultralight airplane, equipped with a gas-powered, V-4 piston engine and two ducted fans that provide the lift.”

Jetpack movies

In May, Swiss daredevil Yves Rossy, “also known Jet Man, Rocket Man, the Bird Man of the Alps,” flew his “jet-powered wing suit” through the Swiss Alps at 186 mph. He was dropped out of an airplane at 7,700 feet to begin his five-minute trip.

Paul MacCready was known for a number of innovations in aviation, in particular human-powered and solar-powered flight. For example, he made history in 1979 when his bicyclist-powered, propeller-engineered plane called the Gossamer Albatross crossed the English Channel.